fix: version the Site's scripts by content so a release never meets a cached old one

The proxy in front of production caches .js and .css for hours. After the
last release the Site got the new index.html with the old site-flow.js,
which wrote to an element the new page no longer has; the error left
"Adicionar ao carrinho" disabled. The web build now addresses every local
script and stylesheet by a hash of its content, replacing the hand-kept
?v= markers, so a new release always loads its own files.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

deploy/Dockerfile.web

@@ -22,7 +22,8 @@ LABEL org.opencontainers.image.title="DTF Site and Kanban" \
       org.opencontainers.image.source="DTF System repository"
 ENV WEB_INDEX=index.html PUBLIC_HOST=invalid.example S3_PUBLIC_ENDPOINT=https://invalid.example
 COPY --from=policy /build/default.conf.template /etc/nginx/templates/default.conf.template
-COPY web/ /usr/share/nginx/html/
+# The HTML from the policy stage, with every asset address versioned.
+COPY --from=policy /build/web/ /usr/share/nginx/html/
 
 # The official entrypoint renders the server configuration at startup and Nginx
 # writes its PID/cache files.  Keep the service non-root while granting it